鉀金屬電池（PMBs）因其低成本和低氧化還原電位，被視為下一代高能量密度儲能技術。然而，親鉀點位對成核與生長行為的具體影響尚不明確，缺乏統合的理論指導材料設計。
本研究基於熱力學的經典成核理論，將鐵（Fe）中心與四個氮（N）原子配位的單原子材料（SAM）應用於三維鉀金屬封裝主體，藉由電子金屬載體相互作用（EMSI）調控電荷分布，從而優化了成核與擴散動力學。單原子作為親鉀點位顯著提升碳纖維基材對鉀的親和性，降低了成核與擴散能壘，引入分級多孔結構進一步增大活性點位暴露，提升離子與電子的傳輸效率。熔融鉀實驗證實Fe-N-PCF具優異親鉀性而使吸附速率大幅提升。此外，此外從成核動力學的角度分析，Scharifker-Hills（SH）模型是研究成核與後續生長機制的典型方法，傳統碳纖維基材因缺乏親鉀點位，導致3D瞬時成核和隨機沉積，產生枝晶。引入單原子構型與孔洞結構後，顯著提升成核速率，增加成核位點，實現均勻的3D漸進成核和緻密沉積。透過i²/imax²與t/tmax的無綱量圖和原位光學顯微鏡（In-situ OM），觀察到沉積行為的顯著轉變，並經原位X射線繞射（In-situ XRD）證實高度可逆的金屬沉積過程。
結果顯示，對稱電池具優異的倍率性能及超過1900小時的穩定循環壽命。Fe-N-PCF@K||PTCDA全電池提供257 W h kg⁻¹的能量密度，並在2000次循環後保持69.7%的容量，更穩定的電壓曲線與0.876V的低電壓遲滯，展現該設計在高能量密度、長壽命及優異動力學方面的潛力與應用前景。

Potassium metal batteries (PMBs), owing to their low cost and low redox potential, are regarded as a promising next-generation high-energy-density energy storage technology. However, the specific influence of potassiophilic sites on nucleation and growth behavior remains unclear, and there is a lack of integrated theoretical guidance for material design.
This study is based on the classical nucleation theory (CNT) within thermodynamics, applying single-atom materials (SAMs) with Fe centers coordinated by four nitrogen atoms (Fe-N) to a three-dimensional potassium metal encapsulating host. By leveraging electron-metal support interaction (EMSI) to modulate charge distribution, the nucleation and diffusion kinetics were optimized. Single atoms, acting as potassiophilic sites, significantly enhanced the affinity of carbon fiber substrates towards potassium, reducing the nucleation and diffusion energy barriers. Furthermore, the introduction of a hierarchical porous structure increased the exposure of active sites, enhancing ion and electron transport efficiency. Molten potassium infusion experiments confirmed that Fe-N-PCF exhibits excellent K-wettability, dramatically accelerating the adsorption rate.
From the perspective of nucleation kinetics, the Scharifker-Hills (SH) model is a typical approach for studying nucleation and subsequent growth mechanisms. Traditional carbon fiber substrates, due to the lack of potassiophilic sites, resulted in 3D instantaneous nucleation and random deposition, leading to dendrite formation. The introduction of the single-atom configuration, combined with the porous structure, significantly increased nucleation rates and available nucleation sites, promoting uniform 3D progressive nucleation and dense deposition. Through i²/imax² and t/tmax dimensionless plots, along with in-situ optical microscopy (OM), a distinct transition in deposition behavior was observed. In-situ X-ray diffraction (XRD) further confirmed the highly reversible metal deposition process.
The results demonstrated that the symmetric cell exhibits excellent rate performance and a remarkable cycling stability exceeding 1900 hours. The Fe-N-PCF@K||PTCDA full cell delivered an energy density of 257 W h kg⁻¹ and retained 69.7% of its capacity after 2000 cycles, showing a more stable voltage profile and a low voltage hysteresis of 0.876V. This design highlights significant potential for high-energy-density, long-life, and kinetically favorable potassium metal batteries, offering promising prospects for future applications.

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